xref: /netbsd-src/sys/kern/init_main.c (revision d48f14661dda8638fee055ba15d35bdfb29b9fa8)
1 /*	$NetBSD: init_main.c,v 1.270 2006/07/01 05:41:10 kardel Exp $	*/
2 
3 /*
4  * Copyright (c) 1982, 1986, 1989, 1991, 1992, 1993
5  *	The Regents of the University of California.  All rights reserved.
6  * (c) UNIX System Laboratories, Inc.
7  * All or some portions of this file are derived from material licensed
8  * to the University of California by American Telephone and Telegraph
9  * Co. or Unix System Laboratories, Inc. and are reproduced herein with
10  * the permission of UNIX System Laboratories, Inc.
11  *
12  * Redistribution and use in source and binary forms, with or without
13  * modification, are permitted provided that the following conditions
14  * are met:
15  * 1. Redistributions of source code must retain the above copyright
16  *    notice, this list of conditions and the following disclaimer.
17  * 2. Redistributions in binary form must reproduce the above copyright
18  *    notice, this list of conditions and the following disclaimer in the
19  *    documentation and/or other materials provided with the distribution.
20  * 3. Neither the name of the University nor the names of its contributors
21  *    may be used to endorse or promote products derived from this software
22  *    without specific prior written permission.
23  *
24  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
25  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
26  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
27  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
28  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
29  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
30  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
31  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
32  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
33  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
34  * SUCH DAMAGE.
35  *
36  *	@(#)init_main.c	8.16 (Berkeley) 5/14/95
37  */
38 
39 /*
40  * Copyright (c) 1995 Christopher G. Demetriou.  All rights reserved.
41  *
42  * Redistribution and use in source and binary forms, with or without
43  * modification, are permitted provided that the following conditions
44  * are met:
45  * 1. Redistributions of source code must retain the above copyright
46  *    notice, this list of conditions and the following disclaimer.
47  * 2. Redistributions in binary form must reproduce the above copyright
48  *    notice, this list of conditions and the following disclaimer in the
49  *    documentation and/or other materials provided with the distribution.
50  * 3. All advertising materials mentioning features or use of this software
51  *    must display the following acknowledgement:
52  *	This product includes software developed by the University of
53  *	California, Berkeley and its contributors.
54  * 4. Neither the name of the University nor the names of its contributors
55  *    may be used to endorse or promote products derived from this software
56  *    without specific prior written permission.
57  *
58  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
59  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
60  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
61  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
62  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
63  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
64  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
65  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
66  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
67  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
68  * SUCH DAMAGE.
69  *
70  *	@(#)init_main.c	8.16 (Berkeley) 5/14/95
71  */
72 
73 #include <sys/cdefs.h>
74 __KERNEL_RCSID(0, "$NetBSD: init_main.c,v 1.270 2006/07/01 05:41:10 kardel Exp $");
75 
76 #include "opt_ipsec.h"
77 #include "opt_kcont.h"
78 #include "opt_multiprocessor.h"
79 #include "opt_ntp.h"
80 #include "opt_pipe.h"
81 #include "opt_posix.h"
82 #include "opt_syscall_debug.h"
83 #include "opt_sysv.h"
84 #include "opt_verified_exec.h"
85 
86 #include "rnd.h"
87 
88 #include <sys/param.h>
89 #include <sys/acct.h>
90 #include <sys/filedesc.h>
91 #include <sys/file.h>
92 #include <sys/errno.h>
93 #include <sys/callout.h>
94 #include <sys/kernel.h>
95 #include <sys/kcont.h>
96 #include <sys/kmem.h>
97 #include <sys/mount.h>
98 #include <sys/proc.h>
99 #include <sys/kthread.h>
100 #include <sys/resourcevar.h>
101 #include <sys/signalvar.h>
102 #include <sys/systm.h>
103 #include <sys/vnode.h>
104 #include <sys/tty.h>
105 #include <sys/conf.h>
106 #include <sys/disklabel.h>
107 #include <sys/buf.h>
108 #include <sys/device.h>
109 #include <sys/exec.h>
110 #include <sys/socketvar.h>
111 #include <sys/protosw.h>
112 #include <sys/reboot.h>
113 #include <sys/user.h>
114 #include <sys/sysctl.h>
115 #include <sys/event.h>
116 #include <sys/mbuf.h>
117 #ifdef FAST_IPSEC
118 #include <netipsec/ipsec.h>
119 #endif
120 #ifdef SYSVSHM
121 #include <sys/shm.h>
122 #endif
123 #ifdef SYSVSEM
124 #include <sys/sem.h>
125 #endif
126 #ifdef SYSVMSG
127 #include <sys/msg.h>
128 #endif
129 #ifdef P1003_1B_SEMAPHORE
130 #include <sys/ksem.h>
131 #endif
132 #include <sys/domain.h>
133 #include <sys/namei.h>
134 #if NRND > 0
135 #include <sys/rnd.h>
136 #endif
137 #ifndef PIPE_SOCKETPAIR
138 #include <sys/pipe.h>
139 #endif
140 #ifdef LKM
141 #include <sys/lkm.h>
142 #endif
143 #ifdef VERIFIED_EXEC
144 #include <sys/verified_exec.h>
145 #endif
146 #include <sys/kauth.h>
147 #include <net80211/ieee80211_netbsd.h>
148 
149 #include <sys/syscall.h>
150 #include <sys/sa.h>
151 #include <sys/syscallargs.h>
152 
153 #include <ufs/ufs/quota.h>
154 
155 #include <miscfs/genfs/genfs.h>
156 #include <miscfs/syncfs/syncfs.h>
157 
158 #include <machine/cpu.h>
159 
160 #include <uvm/uvm.h>
161 
162 #include <dev/cons.h>
163 
164 #include <net/if.h>
165 #include <net/raw_cb.h>
166 
167 extern struct proc proc0;
168 extern struct lwp lwp0;
169 extern struct cwdinfo cwdi0;
170 
171 #ifndef curlwp
172 struct	lwp *curlwp = &lwp0;
173 #endif
174 struct	proc *initproc;
175 
176 struct	vnode *rootvp, *swapdev_vp;
177 int	boothowto;
178 int	cold = 1;			/* still working on startup */
179 #ifndef __HAVE_TIMECOUNTER
180 struct timeval boottime;
181 #endif
182 time_t	rootfstime;			/* recorded root fs time, if known */
183 
184 volatile int start_init_exec;		/* semaphore for start_init() */
185 
186 static void check_console(struct lwp *l);
187 static void start_init(void *);
188 void main(void);
189 
190 /*
191  * System startup; initialize the world, create process 0, mount root
192  * filesystem, and fork to create init and pagedaemon.  Most of the
193  * hard work is done in the lower-level initialization routines including
194  * startup(), which does memory initialization and autoconfiguration.
195  */
196 void
197 main(void)
198 {
199 #ifdef __HAVE_TIMECOUNTER
200 	struct timeval time;
201 #endif
202 	struct lwp *l;
203 	struct proc *p;
204 	struct pdevinit *pdev;
205 	int s, error;
206 	extern struct pdevinit pdevinit[];
207 	extern void schedcpu(void *);
208 #ifdef NVNODE_IMPLICIT
209 	int usevnodes;
210 #endif
211 
212 	/*
213 	 * Initialize the current LWP pointer (curlwp) before
214 	 * any possible traps/probes to simplify trap processing.
215 	 */
216 	l = &lwp0;
217 	curlwp = l;
218 	l->l_cpu = curcpu();
219 	l->l_proc = &proc0;
220 	l->l_lid = 1;
221 
222 	/*
223 	 * Attempt to find console and initialize
224 	 * in case of early panic or other messages.
225 	 */
226 	consinit();
227 
228 	KERNEL_LOCK_INIT();
229 
230 	uvm_init();
231 
232 	kmem_init();
233 
234 	/* Do machine-dependent initialization. */
235 	cpu_startup();
236 
237 	/* Initialize callouts. */
238 	callout_startup();
239 
240 	/* Initialize the buffer cache */
241 	bufinit();
242 
243 	/*
244 	 * Initialize mbuf's.  Do this now because we might attempt to
245 	 * allocate mbufs or mbuf clusters during autoconfiguration.
246 	 */
247 	mbinit();
248 
249 	/* Initialize sockets. */
250 	soinit();
251 
252 #ifdef KCONT
253 	/* Initialize kcont. */
254         kcont_init();
255 #endif
256 
257 	/*
258 	 * The following things must be done before autoconfiguration.
259 	 */
260 	evcnt_init();		/* initialize event counters */
261 #if NRND > 0
262 	rnd_init();		/* initialize RNG */
263 #endif
264 	/* Initialize the sysctl subsystem. */
265 	sysctl_init();
266 
267 	/* Initialize process and pgrp structures. */
268 	procinit();
269 
270 	/* Initialize signal-related data structures. */
271 	signal_init();
272 
273 	/* Create process 0 (the swapper). */
274 	proc0_init();
275 
276 	/*
277 	 * Charge root for one process.
278 	 */
279 	(void)chgproccnt(0, 1);
280 
281 	rqinit();
282 
283 	/* Initialize the file systems. */
284 #ifdef NVNODE_IMPLICIT
285 	/*
286 	 * If maximum number of vnodes in namei vnode cache is not explicitly
287 	 * defined in kernel config, adjust the number such as we use roughly
288 	 * 1.0% of memory for vnode cache (but not less than NVNODE vnodes).
289 	 */
290 	usevnodes = (ptoa((unsigned)physmem) / 100) / sizeof(struct vnode);
291 	if (usevnodes > desiredvnodes)
292 		desiredvnodes = usevnodes;
293 #endif
294 	vfsinit();
295 
296 
297 #ifdef __HAVE_TIMECOUNTER
298 	inittimecounter();
299 	ntp_init();
300 #endif /* __HAVE_TIMECOUNTER */
301 
302 	/* Configure the system hardware.  This will enable interrupts. */
303 	configure();
304 
305 	ubc_init();		/* must be after autoconfig */
306 
307 	/* Lock the kernel on behalf of proc0. */
308 	KERNEL_PROC_LOCK(l);
309 
310 #ifdef SYSVSHM
311 	/* Initialize System V style shared memory. */
312 	shminit();
313 #endif
314 
315 #ifdef SYSVSEM
316 	/* Initialize System V style semaphores. */
317 	seminit();
318 #endif
319 
320 #ifdef SYSVMSG
321 	/* Initialize System V style message queues. */
322 	msginit();
323 #endif
324 
325 #ifdef P1003_1B_SEMAPHORE
326 	/* Initialize posix semaphores */
327 	ksem_init();
328 #endif
329 
330 	/* Initialize kauth. */
331 	kauth_init();
332 
333 #ifdef VERIFIED_EXEC
334 	  /*
335 	   * Initialise the fingerprint operations vectors before
336 	   * fingerprints can be loaded.
337 	   */
338 	veriexec_init_fp_ops();
339 #endif
340 
341 	/* Attach pseudo-devices. */
342 	for (pdev = pdevinit; pdev->pdev_attach != NULL; pdev++)
343 		(*pdev->pdev_attach)(pdev->pdev_count);
344 
345 #ifdef	FAST_IPSEC
346 	/* Attach network crypto subsystem */
347 	ipsec_attach();
348 #endif
349 
350 	/*
351 	 * Initialize protocols.  Block reception of incoming packets
352 	 * until everything is ready.
353 	 */
354 	s = splnet();
355 	ifinit();
356 	domaininit();
357 	if_attachdomain();
358 	splx(s);
359 
360 #ifdef GPROF
361 	/* Initialize kernel profiling. */
362 	kmstartup();
363 #endif
364 
365 	/* Initialize system accouting. */
366 	acct_init();
367 
368 	/* Kick off timeout driven events by calling first time. */
369 	schedcpu(NULL);
370 
371 	/*
372 	 * Create process 1 (init(8)).  We do this now, as Unix has
373 	 * historically had init be process 1, and changing this would
374 	 * probably upset a lot of people.
375 	 *
376 	 * Note that process 1 won't immediately exec init(8), but will
377 	 * wait for us to inform it that the root file system has been
378 	 * mounted.
379 	 */
380 	if (fork1(l, 0, SIGCHLD, NULL, 0, start_init, NULL, NULL, &initproc))
381 		panic("fork init");
382 
383 	/*
384 	 * Create any kernel threads who's creation was deferred because
385 	 * initproc had not yet been created.
386 	 */
387 	kthread_run_deferred_queue();
388 
389 	/*
390 	 * Now that device driver threads have been created, wait for
391 	 * them to finish any deferred autoconfiguration.  Note we don't
392 	 * need to lock this semaphore, since we haven't booted any
393 	 * secondary processors, yet.
394 	 */
395 	while (config_pending)
396 		(void) tsleep(&config_pending, PWAIT, "cfpend", 0);
397 
398 	/*
399 	 * Finalize configuration now that all real devices have been
400 	 * found.  This needs to be done before the root device is
401 	 * selected, since finalization may create the root device.
402 	 */
403 	config_finalize();
404 
405 	/*
406 	 * Now that autoconfiguration has completed, we can determine
407 	 * the root and dump devices.
408 	 */
409 	cpu_rootconf();
410 	cpu_dumpconf();
411 
412 	/* Mount the root file system. */
413 	do {
414 		domountroothook();
415 		if ((error = vfs_mountroot())) {
416 			printf("cannot mount root, error = %d\n", error);
417 			boothowto |= RB_ASKNAME;
418 			setroot(root_device,
419 			    (rootdev != NODEV) ? DISKPART(rootdev) : 0);
420 		}
421 	} while (error != 0);
422 	mountroothook_destroy();
423 
424 	/*
425 	 * Initialise the time-of-day clock, passing the time recorded
426 	 * in the root filesystem (if any) for use by systems that
427 	 * don't have a non-volatile time-of-day device.
428 	 */
429 	inittodr(rootfstime);
430 
431 	CIRCLEQ_FIRST(&mountlist)->mnt_flag |= MNT_ROOTFS;
432 	CIRCLEQ_FIRST(&mountlist)->mnt_op->vfs_refcount++;
433 
434 	/*
435 	 * Get the vnode for '/'.  Set filedesc0.fd_fd.fd_cdir to
436 	 * reference it.
437 	 */
438 	error = VFS_ROOT(CIRCLEQ_FIRST(&mountlist), &rootvnode);
439 	if (error)
440 		panic("cannot find root vnode, error=%d", error);
441 	cwdi0.cwdi_cdir = rootvnode;
442 	VREF(cwdi0.cwdi_cdir);
443 	VOP_UNLOCK(rootvnode, 0);
444 	cwdi0.cwdi_rdir = NULL;
445 
446 	/*
447 	 * Now that root is mounted, we can fixup initproc's CWD
448 	 * info.  All other processes are kthreads, which merely
449 	 * share proc0's CWD info.
450 	 */
451 	initproc->p_cwdi->cwdi_cdir = rootvnode;
452 	VREF(initproc->p_cwdi->cwdi_cdir);
453 	initproc->p_cwdi->cwdi_rdir = NULL;
454 
455 	/*
456 	 * Now can look at time, having had a chance to verify the time
457 	 * from the file system.  Reset p->p_rtime as it may have been
458 	 * munched in mi_switch() after the time got set.
459 	 */
460 	proclist_lock_read();
461 	s = splsched();
462 #ifdef __HAVE_TIMECOUNTER
463 	getmicrotime(&time);
464 #else
465 	mono_time = time;
466 #endif
467 	boottime = time;
468 	LIST_FOREACH(p, &allproc, p_list) {
469 		KASSERT((p->p_flag & P_MARKER) == 0);
470 		p->p_stats->p_start = time;
471 		LIST_FOREACH(l, &p->p_lwps, l_sibling) {
472 			if (l->l_cpu != NULL)
473 				l->l_cpu->ci_schedstate.spc_runtime = time;
474 		}
475 		p->p_rtime.tv_sec = p->p_rtime.tv_usec = 0;
476 	}
477 	splx(s);
478 	proclist_unlock_read();
479 
480 	/* Create the pageout daemon kernel thread. */
481 	uvm_swap_init();
482 	if (kthread_create1(uvm_pageout, NULL, NULL, "pagedaemon"))
483 		panic("fork pagedaemon");
484 
485 	/* Create the filesystem syncer kernel thread. */
486 	if (kthread_create1(sched_sync, NULL, NULL, "ioflush"))
487 		panic("fork syncer");
488 
489 	/* Create the aiodone daemon kernel thread. */
490 	if (kthread_create1(uvm_aiodone_daemon, NULL, &uvm.aiodoned_proc,
491 	    "aiodoned"))
492 		panic("fork aiodoned");
493 
494 #if defined(MULTIPROCESSOR)
495 	/* Boot the secondary processors. */
496 	cpu_boot_secondary_processors();
497 #endif
498 
499 	/* Initialize exec structures */
500 	exec_init(1);
501 
502 	/*
503 	 * Okay, now we can let init(8) exec!  It's off to userland!
504 	 */
505 	start_init_exec = 1;
506 	wakeup(&start_init_exec);
507 
508 	/* The scheduler is an infinite loop. */
509 	uvm_scheduler();
510 	/* NOTREACHED */
511 }
512 
513 void
514 setrootfstime(time_t t)
515 {
516 	rootfstime = t;
517 }
518 
519 static void
520 check_console(struct lwp *l)
521 {
522 	struct nameidata nd;
523 	int error;
524 
525 	NDINIT(&nd, LOOKUP, FOLLOW, UIO_SYSSPACE, "/dev/console", l);
526 	error = namei(&nd);
527 	if (error == 0)
528 		vrele(nd.ni_vp);
529 	else if (error == ENOENT)
530 		printf("warning: no /dev/console\n");
531 	else
532 		printf("warning: lookup /dev/console: error %d\n", error);
533 }
534 
535 /*
536  * List of paths to try when searching for "init".
537  */
538 static const char *initpaths[] = {
539 	"/sbin/init",
540 	"/sbin/oinit",
541 	"/sbin/init.bak",
542 	NULL,
543 };
544 
545 /*
546  * Start the initial user process; try exec'ing each pathname in "initpaths".
547  * The program is invoked with one argument containing the boot flags.
548  */
549 static void
550 start_init(void *arg)
551 {
552 	struct lwp *l = arg;
553 	struct proc *p = l->l_proc;
554 	vaddr_t addr;
555 	struct sys_execve_args /* {
556 		syscallarg(const char *) path;
557 		syscallarg(char * const *) argp;
558 		syscallarg(char * const *) envp;
559 	} */ args;
560 	int options, i, error;
561 	register_t retval[2];
562 	char flags[4], *flagsp;
563 	const char *path, *slash;
564 	char *ucp, **uap, *arg0, *arg1 = NULL;
565 	char ipath[129];
566 	int ipx, len;
567 
568 	/*
569 	 * Now in process 1.
570 	 */
571 	strncpy(p->p_comm, "init", MAXCOMLEN);
572 
573 	/*
574 	 * Wait for main() to tell us that it's safe to exec.
575 	 */
576 	while (start_init_exec == 0)
577 		(void) tsleep(&start_init_exec, PWAIT, "initexec", 0);
578 
579 	/*
580 	 * This is not the right way to do this.  We really should
581 	 * hand-craft a descriptor onto /dev/console to hand to init,
582 	 * but that's a _lot_ more work, and the benefit from this easy
583 	 * hack makes up for the "good is the enemy of the best" effect.
584 	 */
585 	check_console(l);
586 
587 	/*
588 	 * Need just enough stack to hold the faked-up "execve()" arguments.
589 	 */
590 	addr = (vaddr_t)STACK_ALLOC(USRSTACK, PAGE_SIZE);
591 	if (uvm_map(&p->p_vmspace->vm_map, &addr, PAGE_SIZE,
592                     NULL, UVM_UNKNOWN_OFFSET, 0,
593                     UVM_MAPFLAG(UVM_PROT_ALL, UVM_PROT_ALL, UVM_INH_COPY,
594 		    UVM_ADV_NORMAL,
595                     UVM_FLAG_FIXED|UVM_FLAG_OVERLAY|UVM_FLAG_COPYONW)) != 0)
596 		panic("init: couldn't allocate argument space");
597 	p->p_vmspace->vm_maxsaddr = (caddr_t)STACK_MAX(addr, PAGE_SIZE);
598 
599 	ipx = 0;
600 	while (1) {
601 		if (boothowto & RB_ASKNAME) {
602 			printf("init path");
603 			if (initpaths[ipx])
604 				printf(" (default %s)", initpaths[ipx]);
605 			printf(": ");
606 			len = cngetsn(ipath, sizeof(ipath)-1);
607 			if (len == 0) {
608 				if (initpaths[ipx])
609 					path = initpaths[ipx++];
610 				else
611 					continue;
612 			} else {
613 				ipath[len] = '\0';
614 				path = ipath;
615 			}
616 		} else {
617 			if ((path = initpaths[ipx++]) == NULL)
618 				break;
619 		}
620 
621 		ucp = (char *)USRSTACK;
622 
623 		/*
624 		 * Construct the boot flag argument.
625 		 */
626 		flagsp = flags;
627 		*flagsp++ = '-';
628 		options = 0;
629 
630 		if (boothowto & RB_SINGLE) {
631 			*flagsp++ = 's';
632 			options = 1;
633 		}
634 #ifdef notyet
635 		if (boothowto & RB_FASTBOOT) {
636 			*flagsp++ = 'f';
637 			options = 1;
638 		}
639 #endif
640 
641 		/*
642 		 * Move out the flags (arg 1), if necessary.
643 		 */
644 		if (options != 0) {
645 			*flagsp++ = '\0';
646 			i = flagsp - flags;
647 #ifdef DEBUG
648 			printf("init: copying out flags `%s' %d\n", flags, i);
649 #endif
650 			arg1 = STACK_ALLOC(ucp, i);
651 			ucp = STACK_MAX(arg1, i);
652 			(void)copyout((caddr_t)flags, arg1, i);
653 		}
654 
655 		/*
656 		 * Move out the file name (also arg 0).
657 		 */
658 		i = strlen(path) + 1;
659 #ifdef DEBUG
660 		printf("init: copying out path `%s' %d\n", path, i);
661 #else
662 		if (boothowto & RB_ASKNAME || path != initpaths[0])
663 			printf("init: trying %s\n", path);
664 #endif
665 		arg0 = STACK_ALLOC(ucp, i);
666 		ucp = STACK_MAX(arg0, i);
667 		(void)copyout(path, arg0, i);
668 
669 		/*
670 		 * Move out the arg pointers.
671 		 */
672 		ucp = (caddr_t)STACK_ALIGN(ucp, ALIGNBYTES);
673 		uap = (char **)STACK_ALLOC(ucp, sizeof(char *) * 3);
674 		SCARG(&args, path) = arg0;
675 		SCARG(&args, argp) = uap;
676 		SCARG(&args, envp) = NULL;
677 		slash = strrchr(path, '/');
678 		if (slash)
679 			(void)suword((caddr_t)uap++,
680 			    (long)arg0 + (slash + 1 - path));
681 		else
682 			(void)suword((caddr_t)uap++, (long)arg0);
683 		if (options != 0)
684 			(void)suword((caddr_t)uap++, (long)arg1);
685 		(void)suword((caddr_t)uap++, 0);	/* terminator */
686 
687 		/*
688 		 * Now try to exec the program.  If can't for any reason
689 		 * other than it doesn't exist, complain.
690 		 */
691 		error = sys_execve(l, &args, retval);
692 		if (error == 0 || error == EJUSTRETURN) {
693 			KERNEL_PROC_UNLOCK(l);
694 			return;
695 		}
696 		printf("exec %s: error %d\n", path, error);
697 	}
698 	printf("init: not found\n");
699 	panic("no init");
700 }
701